From 1st April to 31st May, it has grown by nearly 52%. While, this is half the picture, considering not all sign into Nokia account using Facebook only. But, this is significant because Nokia accounts are being used for all Asha, Symbian and Lumia devices. Symbian is on decline sadly, so this growth must have come from Lumia and Asha devices. Especially the major growth which can be seen from May onwards of about 45% coincides well with onslaught of likes of Lumia 520, 720. So, that may say something about Nokia making a comeback or it is too early to imagine that?
Thanks Tellus for the tip!